The abdomen does not lie, but the labs might: Predictors of intra-abdominal injury on computed tomography imaging in pediatric blunt trauma patients.

Introduction: Multiple studies have indicated that isolated abnormal laboratory results necessitate obtaining abdominal computed tomography (CT) for pediatric patients with blunt abdominal trauma (BAT), regardless of the normal abdominal examination. This study aims to identify the predictors of intra-abdominal injury (IAI) and the role of laboratory tests in CT imaging among pediatric BAT patients.

Methods: This is a retrospective review at a Level II pediatric trauma center (2018-2022). Children (younger than 18 years) who presented with BAT and received abdominal CT imaging were included. Outcomes were rates of IAI and interventions. Multivariable regression analysis was performed.

Results: Over 5 years, 483 patients met the inclusion criteria. The mean age was 13 years, 58.2% were male, and the median Glasgow Coma Scale was 15. Overall, 19.3% had abdominal pain; 6.2%, postinjury emesis; 26.1%, abdominal tenderness; and 10.6%, pelvic tenderness. On initial imaging, 7.0% had a positive focused assessment with sonography in trauma examination, and 7.2% had an abnormal plain x-ray. On initial laboratory testing, 7.9% had abnormal serum aspartate aminotransferase (AST), 3.1% had abnormal hematocrit, 1.2% had abnormal urine analysis, and 0.8% had abnormal lipase. Seventeen percent had at least one IAI, of which 17% underwent intervention. Multivariable regression analysis identified abdominal tenderness, abnormal plain x-ray, positive focused assessment with sonography in trauma, blood transfusion requirements, and abnormal AST as independent predictors of IAI on abdominal CT imaging. Moreover, among patients with IAI, only 37.3% had abnormal laboratory results, and all had at least one of the predictors of IAI (in addition to or other than abnormal AST). Among patients with abnormal laboratory results (n = 57), nine patients had none of the predictors of IAI, out of which none were found to have IAI on abdominal CT.

Conclusion: More than 80% of all abdominal CT imaging had negative results. Our findings highlight the significance of clinical findings in the trauma bay, regardless of laboratory findings, when deciding to order abdominal CT imaging for pediatric BAT patients.

Level of evidence: Therapeutic/Care Management; Level III.